1. Field of the Invention
The invention relates to apparatus for copolymerizing at least two gaseous monomers which permits the precise control over the introduction of the type and amount of gaseous monomer into a reaction chamber for copolymerization. The apparatus of the present invention is useful in copolymerizing olefinic monomers, such as propylene and ethylene, although any other gaseous monomers including ethylene oxide and propylene oxide can be copolymerized in it. The apparatus of the present invention further is useful in producing gradient copolymers in which the composition of the copolymer varies gradually along the copolymer chain. It can also be used for producing block copolymers which comprise polymerized blocks of one comonomer connected to polymerized blocks of another comonomer. The invention is also useful in the copolymerization of comonomers in random fashion and permits accurate and precise controls over the amount and type of monomer being copolymerized at any given time.
2. Description of the Prior Art
Heretofore, previous techniques and apparatus for mixing two gaseous monomers involved either a constant composition controlled by relative partial pressures in a reactor or involved occasional pulsing of one gaseous monomer into the other gaseous monomer line leading to the reactor. Such prior art techniques and apparatus were difficult to control because of the lack of means for regulating precisely the flow of the respective gaseous comonomers into the reactor. Furthermore, the prior art apparatus was not able to produce gradient copolymers wherein the composition changes gradually and continually along the polymer chain. No prior art is known to exist which represents a way to control precisely the composition of the gaseous monomer mixture sent to the reactor and to continually vary this composition over a predetermined compositional profile.
Bassett et al., U.S. Pat. No. 3,804,881, and Knopf et al., U.S. Pat. No. 3,839,293, disclose the process of continuously introducing a primary polymerizable feed composition from a primary feed source to a polymerization zone, wherein the primary polymerizable feed composition is continually varying in compositional content during the continuous introduction; a different secondary polymerizable feed composition from a secondary feed source is simultaneously added to the primary feed source so as to continually change the compositional content of reactants in the primary feed source; and the reactants introduced to the polymerization zone are polymerized.
Neither of these patents discloses, teaches or suggests the apparatus of this invention.
British Pat. No. 1292226 relates to the manufacture of ion exchange resins by polymerizing styrene and divinylbenzene (DVB) in bead form in steps of increasing DVB content in order to maintain a given DVB level in the bead because of the greater reactivity of DVB compared to styrene. This patent does not teach, disclose or suggest the apparatus of this invention.